Magnetoresistance of high mobility HgTe quantum dot films with controlled charging

Funding: We thank Christopher Melnychuk for very useful discussions. This work was supported by the National Natural Science Foundation of China under grant number 62105022, the University of Chicago Materials Research Science and Engineering Center, which was funded by the National Science Foundation under award number DMR1420709, and by the Department of Defense (DOD) Air Force Office of Scientific Research under grant number FA9550-18-1-0099.The magnetoresistance of HgTe quantum dot films, exhibiting a well-defined 1Se state charging and a relatively high mobility (1-10 cm2 V−1 s−1), is measured as a function of temperature down to 10 K and controlled occupation of the first electronic state. There is a positive-quadratic magnetoresistance which can be several 100% at low temperature and scales like x(1 − x) where x is the filling fraction of the lowest quantum dot state in the conduction band, 1Se. This positive magnetoresistance is orders of magnitude larger than the effect estimated from mobile carriers and it is attributed to the increased confinement induced by the magnetic field. There is also a negative magnetoresistance of 1-20% from 300 K to 10 K which is rather independent of the fractional occupation, and which follows a negative exponential dependence with the magnetic field. It can be empirically fit with an effective g-factor of ∼55 and it is tentatively attributed to the reduction of barrier heights by the Zeeman splitting of the 1Se state.Peer reviewe

INTEnsive care bundle with blood pressure reduction in acute cerebral hemorrhage trial (INTERACT3): Study protocol for a pragmatic stepped-wedge cluster-randomized controlled trial

Background: Early intensive blood pressure (BP) lowering remains the most promising treatment for acute intracerebral hemorrhage (ICH), despite discordant results between clinical trials and potential variation in the treatment effects by approach to control BP. As the third in a series of clinical trials on this topic, the INTEnsive care bundle with blood pressure Reduction in Acute Cerebral hemorrhage Trial (INTERACT3) aims to determine the effectiveness of a goal-directed care bundle protocol of early physiological control (intensive BP lowering, glycemic control, and pyrexia treatment) and reversal of anticoagulation, in acute ICH.Methods: INTERACT3 is a pragmatic, international, multicenter, stepped-wedge (4 phases/3 steps), cluster-randomized controlled trial to determine the effectiveness of a multifaceted care package in adult (age ≥ 18 years) patients (target 8360) with acute ICH (\u3c 6 h of onset) recruited from 110 hospitals (average of 19 consecutive patients per phase) in low- and middle-income countries. After a control phase, each hospital implements the intervention (intensive BP lowering, target systolic \u3c 140 mmHg; glucose control, target 6.1-7.8 mmol/L and 7.8-10.0 mmol/L in those without and with diabetes mellitus, respectively; anti-pyrexia treatment to target body temperature ≤ 37.5 °C; and reversal of anticoagulation, target international normalized ratio \u3c 1.5 within 1 h). Information will be obtained on demographic and baseline clinical characteristics, in-hospital management, and 7-day outcomes. Central trained blinded assessors will conduct telephone interviews to assess physical function and health-related quality of life at 6 months. The primary outcome is the modified Rankin scale (mRS) at 6 months analyzed using ordinal logistic regression. The sample size of 8360 subjects provides 90% power (α = 0.05) to detect a 5.6% absolute improvement (shift) in the primary outcome of the intervention versus control standard care, with various assumptions.Discussion: As the largest clinical trial in acute ICH, INTERACT3 is on schedule to provide an assessment of the effectiveness of a widely applicable goal-directed care bundle for a serious condition in which a clearly proven treatment has yet to be established.Trial registration: ClinicalTrials.gov NCT03209258. Registered on 1 July 2017. Chinese Trial Registry ChiCTR-IOC-17011787. Registered on 28 June 2017

Who is the main caregiver of the mother during the doing-the-month : is there an association with postpartum depression?

Background: To examine the relationship between the main caregiver during the “doing-the-month” (a traditional Chinese practice which a mother is confined at home for 1 month after giving birth) and the risk of postpartum depression (PPD) in postnatal women. Methods: Participants were postnatal women stayed in hospital and women who attended the hospital for postpartum examination, at 14–60 days after delivery from November 1, 2013 to December 30, 2013. Postpartum depression status was assessed using the Edinburgh Postnatal Depression Scale. Univariate and multivariable logistic regressions were used to identify the associations between the main caregiver during “doing-the-month” and the risk of PPD in postnatal women. Results: One thousand three hundred twenty-five postnatal women with a mean (SD) age of 28 (4.58) years were included in the analyses. The median score (IQR) of PPD was 6.0 (2, 10) and the prevalence of PPD was 27%. Of these postnatal women, 44.5% were cared by their mother-in-law in the first month after delivery, 36.3% cared by own mother, 11.1% by “yuesao” or “maternity matron” and 8.1% by other relatives. No association was found between the main caregivers and the risk of PPD after multiple adjustments. Conclusions: Although no association between the main caregivers and the risk of PPD during doing-the-month was identified, considering the increasing prevalence of PPD in Chinese women, and the contradictions between traditional culture and latest scientific evidence for some of the doing-the-month practices, public health interventions aim to increase the awareness of PPD among caregivers and family members are warranted

ALS-Associated E478G Mutation in Human OPTN (Optineurin) Promotes Inflammation and Induces Neuronal Cell Death

Amyotrophic Lateral Sclerosis (ALS) is a group of neurodegenerative disorders that featured with the death of motor neurons, which leads to loss of voluntary control on muscles. The etiologies vary among different subtypes of ALS, and no effective management or medication could be provided to the patients, with the underlying mechanisms incompletely understood yet. Mutations in human Optn (Optineurin), particularly E478G, have been found in many ALS patients. In this work, we report that NF-κB activity was increased in Optn knockout (Optn−/−) MEF (mouse embryonic fibroblast) cells expressing OPTN of different ALS-associated mutants especially E478G. Inflammation was significantly activated in mice infected with lenti-virus that allowed overexpression of OPTNE478G mutation in the motor cortex, with marked increase in the secretion of pro-inflammatory cytokines as well as neuronal cell death. Our work with both cell and animal models strongly suggested that anti-inflammation treatment could represent a powerful strategy to intervene into disease progression in ALS patients who possess the distinctive mutations in OPTN gene

INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4) : study protocol for a randomized controlled trial

Background: Early pre-hospital initiation of blood pressure (BP) lowering could improve outcomes for patients with acute stroke, by reducing hematoma expansion in intracerebral hemorrhage (ICH), and time to reperfusion treatment and risk of intracranial hemorrhage in ischemic stroke (IS). We present the design of the fourth INTEnsive ambulance-delivered blood pressure Reduction in hyper-ACute stroke Trial (INTERACT4). Methods: A multi-center, ambulance-delivered, prospective, randomized, open-label, blinded endpoint (PROBE) assessed trial of pre-hospital BP lowering in 3116 hypertensive patients with suspected acute stroke at 50+ sites in China. Patients are randomized through a mobile phone digital system to intensive BP lowering to a target systolic BP of < 140 mmHg within 30 min, or guideline-recommended BP management according to local protocols. After the collection of in-hospital clinical and management data and 7-day outcomes, trained blinded assessors conduct telephone or face-to-face assessments of physical function and health-related quality of life in participants at 90 days. The primary outcome is the physical function on the modified Rankin scale at 90 days, analyzed as an ordinal outcome with 7 categories. The sample size was estimated to provide 90% power (α = 0.05) to detect a 22% reduction in the odds of a worse functional outcome using ordinal logistic regression. Discussion: INTERACT4 is a pragmatic clinical trial to provide reliable evidence on the effectiveness and safety of ambulance-delivered hyperacute BP lowering in patients with suspected acute stroke. Trial registration: ClinicalTrials.gov NCT03790800. Registered on 2 January 2019; Chinese Trial Registry ChiCTR1900020534. Registered on 7 January 2019. All items can be found in this protocol paper

Pressor therapy in acute ischaemic stroke: an updated systematic review

Background Low blood pressure (BP) in acute ischaemic stroke (AIS) is associated with poor functional outcome, death, or severe disability. Increasing BP might benefit patients with post-stroke hypotension including those with potentially salvageable ischaemic penumbra. This updated systematic review considers the present evidence regarding the use of vasopressors in AIS. Methods We searched the Cochrane Database of Systematic Reviews, MEDLINE, EMBASE and trial databases using a structured search strategy. We examined reference lists of relevant publications for additional studies examining BP elevation in AIS. Results We included 27 studies involving 1886 patients. Nine studies assessed increasing BP during acute reperfusion therapy (intravenous thrombolysis, mechanical thrombectomy, intra-arterial thrombolysis or combined). Eighteen studies tested BP elevation alone. Phenylephrine was the most commonly used agent to increase BP (n = 16 studies), followed by norepinephrine (n = 6), epinephrine (n = 3) and dopamine (n = 2). Because of small patient numbers and study heterogeneity, a meta-analysis was not possible. Overall, BP elevation was feasible in patients with fluctuating or worsening neurological symptoms, large vessel occlusion with labile BP, sustained post-stroke hypotension and ineligible for intravenous thrombolysis or after acute reperfusion therapy. The effects on functional outcomes were largely unknown and close monitoring is advised if such intervention is undertaken. Conclusion Although theoretical arguments support increasing BP to improve cerebral blood flow and sustain the ischaemic penumbra in selected AIS patients, the data are limited and results largely inconclusive. Large, randomised controlled trials are needed to identify the optimal BP target, agent, duration of treatment and effects on clinical outcomes.acceptedVersio

Transport Property on Mercury Chalcogenide Colloidal Quantum Dot

Beginning in the early 1980s and extending to the present, colloidal nanocrystals(NC) have become an important class of materials with great potential for applications ranging from medicine to electronic and optoelectronic devices. Semiconductor NCs, for example, hold unique promise for near- and mid-infrared technologies, where very few semiconductor materials are available. Mercury chalcogenide colloidal quantum dots(QD) are of interest as solution based materials in the mid-IR spectral range. Aggregated HgTe QDs are typically undoped or lightly p-doped with size-dependent bandgaps and have shown promise as mid-IR detectors, as proved by Keuleyan et al in 2011. In contrast to aggregated HgTe, non-aggregated mercury chalcogenide QDs are usually stably n-doped in ambient conditions, which allowed the realizations of QDs intraband photodetectors. These materials have made great progress in mid-IR detection in the last few years including background limited photovoltaic (PV) devices, and are expected to lead to the simplified fabrication of high resolution mid-infrared cameras, Plasmon resonance enhanced PV devices and multi-spectral detectors. The performances of some NC-based mid-IR devices have already been comparable with the current commercial epitaxial devices. The precise engineering of the electronic interactions and wave functions with nanomaterials is a promising avenue for further improvement, which is the main project of my Ph.D. project. This thesis focuses on a deeper understanding of electrical transport in nanoparticle solids when carriers must travel via the nanocrystal states. In chapter 2, I use electrochemistry to provide the measurement of the Fermi level and the absolute measurements of the filled and empty state energies with the application of a voltage. This work helps to obtain the energy structure and doping level of those mercury chalcogenide QDs. In chapter 3, I present the work on HgTe/Se QD films which show high mobility for charges transported through discrete QD states. A hybrid surface passivation process efficiently eliminates surface states, provides tunable air-stable doping, and enables hysteresis-free filling of QD states evidenced by strong conductance modulation. In chapter 4, I show the size polydispersity effect on HgSe colloidal quantum dot. The results show mobility quite exponentially dependent on size dispersion, indicating the dispersion causes effect related to the activation energy. This effect could be from the monodispersed quantum dots narrowing the energy difference between sites, which causes the reduction in the barrier height for transport. In chapter 5, I discuss the magnetic transport properties on HgTe QDs. A positive-quadratic magnetoresistance is observed which can be several 100% at low temperature and scales like x (1- x) where x is the fractional occupation of the 1Se state. There is also a negative magnetoresistance of 1-20% from 300 K to 10 K which is rather independent of the fractional occupation, and which follows a negative exponential dependence with the magnetic field. In chapter 6, I take HgTe QD as an example, showing that the high carrier mobility is generally beneficial for QD device applications

Confucianism and the altruistic behaviour in the succession of family firms: evidence from asset write-downs

ABSTRACTThis paper explores how Confucianism influences the altruistic behaviour during family firm successions. Using a sample of Chinese listed family firms which have transferred the power to family successors during 2005-2018, we find that family firms deeply influenced by Confucianism intend to take a big bath via asset write-downs in the year before the succession. Confucianism has stronger influence on altruism when the successor have closer blood relationship with the founder, when the successor is less educated, when the family have weaker control over the firm or when the firm is in a lower market position. When the board of directors is more independent or the auditor has higher reputation, the influence of Confucianism is weaker. Family firms with more asset write-downs have better short-term performance after the succession, but lower business reform and R&D inputs. These findings enrich the research on Confucianism and corporate governance of family firms